.box {
  width: 800px;
  height: 600px;
  border: 1px solid black;
  margin: 50px auto;

  display: flex;
  flex-direction: column;
}

.box > ul {
  width: 100%;
  height: 60px;
  /* background-color: coral; */
  display: flex;
}

.box > ul > li {
  /* width: 100%; */
  flex-grow: 1;
  height: 100%;
  background-color: orange;
  display: flex;
  justify-content: center;
  align-items: center;
  color: white;
  font-size: 20px;
}

.box > ul > li.active {
  background-color: darkorange;
}

.box > ol {
  width: 100%;
  /* height: 50px; */
  flex-grow: 1;
  background-color: burlywood;
  position: relative;
}

.box > ol > li {
  width: 100%;
  height: 100%;
  position: absolute;
  left: 0;
  top: 0;
  display: none;
  justify-content: center;
  align-items: center;
  color: white;
  font-size: 50px;
}

.box > ol > li.active {
  display: flex;
}
